This line in the changelog is referring to filters, not patterns. The difference is that patterns determine whether a route matches and which parts of the URL should be extracted while filters are functions that are called before the route’s action is called. They allow to make sure a route action is only called if the user is authenticated for example. Filters are being used for the Panel and are a very specific and advanced feature.
The syntax for patterns is a regular expression and not specific to Kirby.
As @lukasbestle explained, the pipe syntax refers to filters, to separate multiple filter, you can use a pipe |. But in your current use case, I don’t think that’s what you need.